function womensAge(n) {
    for (var i = 2;; i++) {
        if (2 * i + 1 === n) return `${n}? That's just 21, in base ${i}!`
        if (2 * i === n) return `${n}? That's just 20, in base ${i}!`
    }
}
console.log(womensAge(83))